Cardiometabolic profile of different body composition phenotypes in children.

Context Cardiometabolic profiles of different body composition phenotypes are poorly characterized in young children, where it is well-established that high adiposity is unfavorable, but the role of lean mass is unclear. Objective We hypothesized that higher lean mass attenuates cardiometabolic risk in children with high fat mass. Design, setting, participants In 6-year-old children (n=377) from the Growing Up in Singapore Towards healthy Outcomes (GUSTO) prospective birth cohort, whole-body composition was measured by quantitative magnetic resonance, a novel validated technology. Based on fat mass index (FMI) and lean mass index (LMI), 4 body composition phenotypes were derived: low FMI-low LMI (LF-LL), low FMI-high LMI (LF-HL), high FMI-low LMI (HF-LL), high FMI-high LMI (HF-HL). Main outcome measures BMI z-score, fasting plasma glucose, insulin resistance, metabolic syndrome risk score, fatty liver index, and blood pressure. Results Compared to the LF-HL group, children in both high FMI groups had increased BMI z-score (HF-HL: 1.43units 95% CI [1.11,1.76]; HF-LL: 0.61units [0.25,0.96]) and metabolic syndrome risk score (HF-HL: 1.64 [0.77,2.50]; HF-LL: 1.28 [0.34,2.21]). The HF-HL group also had increased fatty liver index (1.15 [0.54,1.77]). Girls in HF-HL group had lower fasting plasma glucose (-0.29mmol/L [-0.55,-0.04]) and diastolic blood pressure (-3.22mmHg [-6.03,-0.41]) than girls in the HF-LL group. No similar associations were observed in boys. Conclusions In a multi-ethnic Asian cohort, lean mass seemed to protect against some cardiometabolic risk markers linked with adiposity, but only in girls. Fat mass index seemed more important than lean mass index in relation to cardiometabolic profiles of young children.